How can I parent multiple meshes to one bone?
So, as explained by Jaroslav, the basic way to do it is to switch your armature to Pose mode, then select your object, select the bone you want to parent to, and parent with ctrlP > Bone.

You also have this solution, better if you'll need to join the objects or some other cases, so it really depends on the situation:


First deparent the objects from the armature. If you want to deparent several objects at once, select all your objects, select one last (make it the active one), deparent it, then in the Properties panel > Object > Relations, right click on the Parent field and choose Copy To Selected.
Now select your objects and parent to the armature With Empty Groups, which means that each object will have vertex groups created with the names of the bones, except none of these groups are assigned to vertices yet.
Then select each of your object, go in Edit mode, and in the Properties panel > Data > Vertex Groups, assign to the object the group it is supposed to be part of, meaning the bone it is supposed to be controlled by (it looks like it's the root you want).